The Aggrandizer moves into viability

 As I mentioned previously, I'm tangentially involved in an effort to put up an innovative 1.25M repeater here in the metro. The majority of the effort has come from KE0NA (Dave), with considerable help and advice from N0YNT (Matt). Originally, the repeater was planned to take the place of the failed TCRC 224.540- machine in Burnsville, as it had a duplexer, antenna, and site sitting unused. With Dave being the Vice-President of the TCRC, it seemed to be a "done deal", and the TCRC would be the test bed for an innovative concept -- which is kind of what radio clubs are supposed to do.

 No such luck, however. The President of the TCRC, WB0JMG (Artie), unilaterally decreed not only that the repeater we designed would not be put into service on any TCRC site, but he also strictly forbade any club "resources" to be used in the effort -- such as advice or technical help. 

Surely this innovative repeater design must be some kind of dangerous and crazy scheme, right? The wisest course would be to deny the amateur community the use of of one of the few 1.25M repeaters for months on end, rather than take the outrageous risk of even testing this concept, which is clearly doomed to failure and disgrace. Right? That's the only reasonable explanation. 

So, what is this wild and uproariously laughable idea that must be put down and unceremoniously buried? 

It's simply this: put two TYT TH-9000 mobile 1.25M transceivers back to back, with a controller mediating. 

Gear for the 222 MHz band is hard to come by. There aren't a lot of old commercial repeaters sitting around (as is the case with 2M and 70cm) to press into service and use in amateur radio. The TH-9000 is uniquely designed to be used as a repeater, with an internal header that provides TX and RX audio, COS, PTT, and +5 vDC. It only has about 45W RF output, but it can certainly drive a PA. Even at 45W, the metro area could be fairly well covered, especially with a good site and antenna. 

Since this is different from how repeaters are normally operated, there was no shortage of "experts" dismissing the idea out-of-hand. We can't be 'experimenting', after all. This is amateur radio! There are no new ideas; only bad ones that experts laugh at. 

Undeterred, we went ahead with the project. Barred from using any TCRC expertise, Matt set up a controller. Matt is a member of the TCRC (as am I), but we are not part of the club's "Tech Team", and so we considered ourselves unbound by the President's decree. The repeater, now named "The Aggrandizer", was field tested at the July AITP event. It didn't "de-sense", and worked an HT from about a mile away. Moving forward from that point, I prevailed upon K0LAV (Paul) and K9EQ (Chris) for advice, and Dave consulted with KA0KMJ (John), as these were hams free of any restrictions placed on them by the TCRC. 

As it now stands, Dave has set up a transmitting antenna at his home in NE Minneapolis for The Aggrandizer. He got it provisionally co-ordinated for 224.240-, which is the 1.25M SNP pair. As he mastered the mysteries of the controller, he set up a voice ID to "beacon" every ten minutes. The next step is the installation of a receiving antenna, which is challenging because he doesn't have a duplexer. Like everything else on 1.25M, duplexers are quite scarce.

KA0KMJ confirmed last week the the signal was reaching his home in Osseo. I also drove around Crystal, New Hope, Plymouth, and Golden Valley listening to the beacon on my Kenwood F6-A. The antenna at Dave's is only about 25 feet up, and in an area that isn't particularly elevated, but I received the signal at S9 in most places on my drive. There were some low spots at only S2, but that's to be expected with a "compromise" site. 

The propagation characteristics of the 222 MHz band are pretty favourable for amateur use. It has coverage beyond "line of sight" like VHF, but it still has some ability to reflect off objects like UHF. Ideally, 1.25M is a better choice for urban and suburban amateur radio than 2M is, but 2M got a huge advantage in the early goings from the availability of VHF commercial gear. 

At some point, this project will produce a working 1.25M repeater. It will probably happen before the TCRC gets the .540 back on the air. If the TCRC would relent, it could be on the air immediately, and I would happily provide a 100W PA to make it the best 1.25M repeater in the State. They have a duplexer and antenna on a great site that are just sitting unused. 

Let's look at the Mission Statement of the Twin Cities Repeater Club: 

The purpose of the TCRC is to facilitate the local communication needs of its members by owning and operating a state of the art wide area coverage two meter repeater system. The club will further involve itself in secondary activities intended to (1) promote the exchange of ideas and information related to amateur radio, (2) strengthen the fellowship and camaraderie among the members, (3) serve the local amateur radio community, and (4) increase local public safety.

Okay, so it's all about 2M now. Good to know. Maybe we already did. I'm left wondering how an Order of Silence from the President on this project promotes "the exchange of ideas and information related to amateur radio", though. If this concept works, it could make it pretty easy to not only set up 1.25M repeaters in any community, but also UHF repeaters, since there are UHF TH-9000's. We can't allow hams to set up cheap repeaters and learn how duplexers and controllers work, can we? It's all so "experimental", which is what amateur radio is apparently there to prevent. These secrets must be carefully guarded, and only revealed to those that our Wise Elders deem worthy... and in possession of sufficient disposable income. 

I know that KE0NA has described the experience gained from this project as "priceless". It's certainly been an educational experience for me as well, in my limited role. And KD0ZWN (Josh) has been inspired to experiment with Raspberry Pi controllers due to his involvement in this secretive and forbidden project. Even the experienced hams that we asked for advice had to do a little "re-thinking" of the conventional wisdom. 

The Aggrandizer will on display (in all its horror) at the September AITP event next weekend, where another field test will be done. Bring a 222 MHz HT and test it out. 

Dave has documented every step of this effort meticulously. He will be able to produce step-by-step instructions that will enable virtually any ham to replicate this for themselves. This information will be available on this blog. There is documentation to show you how to wire the headers of the TH-9000. There is detailed information on how to connect a controller between the two radios. He explains how to add extra heat sink capability. With sufficient vertical separation between the TX and RX antennae, or with a split site arrangement, you can create your own repeater without a duplexer. Of course, this is all a lot easier on UHF, where there is 5 MHz separating the TX and RX frequencies, and duplexers for the band are plentiful and relatively cheap. And, at the end of day, if you wish to take it all down, you have two new mobile transceivers rather than one ancient repeater. 

It's not just repeaters that are made relatively simple by the accommodations of the TH-9000. APRS digipeaters and gateways are made possible with the VHF model. Auxiliary RF links between repeaters for cross-band functionality or remote receive sites are also likewise simplified with the UHF model. Connections for EchoLink, too, are simplified. You can set up that simplex node that you've thought about. Unlike two metres, there are a whole lot of open frequency pairs on 222 MHz to set up repeaters on, even at the 'hobby' level. Experiment! Set up the first EchoLink-capable 1.25M repeater in the State. Make a cross-band UHF/1.25M repeater happen. Set up 1.25M APRS. Why not have a VHF digipeater at your cabin? It's all possible, and it's all an excellent chance to learn and teach others from your experience.

Behold The Aggrandizer!

As Dave makes progress, your signal reports will be helpful. The beacon isn't always on, but if you hear it on 224.240, it would be nice for us to know. When the receiving antenna goes up, those reports will be even more valuable. If nothing else, check out this innovative repeater at the AITP event. Maybe you will be inspired to join the effort...unless someone orders you not to. 

It's gratifying to me that there are experienced hams out there willing to think "outside the box" and help bring new projects into being. I especially appreciate people like Dave and Matt, who say "Let's make it happen!" instead of smugly explaining "That will never work!". The purveyors of 'conventional wisdom' are many, and they receive a disproportionate amount of respect for merely parroting the worn-out notion that FM is limited to two metres. 

Have we, as a community, become so hidebound and backward-looking that we risk becoming a parody of the visionaries that first established the two-metre infrastructure here in the metro? Are our clubs, which were supposed to leverage the power of their membership into progress, now nothing more than museums and refuges for those obsessed with preserving the past? If so, then the hobby has to look to the few that can still summon the spirit that will move us into the future. 

EDIT: Apparently some people are confused as to the difference between the TCRC and the TCFMC. KE0NA is the VP of the TCRC, not the TCFMC. This post has nothing to with the TCFMC.

EDIT: N0FKM (Dan) has approached N0YNT (Matt) with a potential offer of practical help with this project, possibly teaming up with Dave and Matt to put The Aggrandizer on the air. Dan operates repeaters on three bands in the metro.